AB1381 DETECTION OF QUANTITATIVE ULTRASOUND CHANGES AFTER CORTICOID INFILTRATION OF THE PREACHILLEAL BURSA IN PATIENTS WITH INFLAMMATORY OR MECHANICAL ENTHESOPATHIES
Authors: C. Guillén-Astete, M. Tortosa-Cabañas, Á. Andreu-Suárez
Journal: Annals of the Rheumatic Diseases (2022)

Background It has recently been demonstrated that computer analysis of static ultrasound images can detect exercise-induced stromal changes in the body’s load-bearing tendons. Objectives The purpose of this study is to determine if the same analysis can detect enthesic changes in patients who have undergone corticosteroid infiltration in the preachilles bursa. Methods Serial images of patients who received corticosteroid injections (around 40mg of triamcinolone acetonide) in the preachilles bursa were selected. For the records to be considered it was necessary at least one baseline ultrasound study, one between the first and second month after the injection and one between the third and sixth month after the injection. All images were obtained with the same ultrasound equipment, by the same operator and with the same gain and frequency settings. The images were analyzed using the ImageJ 1.53e program, which allowed the recording of the mean intensity of gray (MIG), dispersion of gray intensities (DIG) and mode of gray intensities (MoIG). Results Eighteen image collections from the same number of patients were selected. Eight corresponded to mechanical enthesopathies (without any diagnosis of spondyloarthritis) and ten were patients with a diagnosis of axial spondyloarthritis (5) or psoriatic arthritis (5). The ratios of MIG, DIG and MoIG of the injured enthesis with respect to its control were, respectively, 1.12 SD 0.14, 0.88 SD 0.42 and 2.04 SD 1.54 for the mechanical pathology group and 0.89 SD 0.05, 1 SD 0.04 and 0.96 SD 0.03 for the inflammatory pathology group. Statistically significant differences in the MIG ratio were detected between patients with inflammatory diseases and patients with mechanical injuries (t=4.69, P=.000). Among patients with inflammatory pathology, the change between baseline and 3-6 months after infiltration MIG was statistically significant (82.59 SD 37.68 vs 92.02 SD 38.67; t=-5.69, P=.000). The changes between DIG and MoIG were not significant (t=0.899, P=.392 and t=-1.542, P=.158, respectively). Among patients with mechanical pathology, there were no significant differences between final and baseline MIG, DIG, or MoIG (t=1.921, P=.096; t=-1.533, P=0.169; and t=1.761, P=0.122, respectively). Figure 1 summarizes the changes in the mean gray intensity index (iMIG) in patients with mechanical and inflammatory pathology. In patients with inflammatory diseases, the changes between the final and basal iMIG tend to normalize (approaching the unit). In the mechanical pathology group, the iMIG variation shows a less defined behavior. Figure 1. Box and whisker plot showing the evolution over time of the pathological/healthy gray intensity mean coefficient. MIGp: Mean gray intensity in the pathological enthesis. MIGc: Mean gray intensity in the control enthesis of the same patient. Conclusion The computer analysis of static images in gray scale can detect the changes observed in the Achilles enthesis of patients with inflammatory diseases such as spondyloarthritis. It is also demonstrated that in these patients the gray intensity change rate tends to be normalized (approaching the unit) after a steroid injection. Trend to normalization has not been evidenced in patients with mechanical pathology. Corticosteroids apparently do not act on the origin of the mechanical enthesopathies. Therefore, the study of the average, dispersion and fashion of gray intensities is erratic. The capacity of MIG detecting evolutionary changes in inflammatory pathology shows a potential for the follow-up of patients with spondyloarthritis and entheseal commitment. Disclosure of Interests Carlos Guillén-Astete Speakers bureau: Novartis, Janssen, Abbvie, Grunenthal, UCB and Gebro., Paid instructor for: Roche, Novartis, Janssen, Esteve and Menarini., Consultant of: Janssen, Novartis and Roche., Grant/research support from: Pfizer, Grunenthal, Gebro and Novartis., Marina Tortosa-Cabañas: None declared, África Andreu-Suárez: None declared